Hi,

I am having issues getting slurm to run multiple jobs in parallel on the same machine.

Most of our jobs are either (relatively) low on CPU and high on memory (data processing) or low on memory and high on CPU (simulations). The server we have is generally big enough (256GB Mem; 16 cores) to accommodate multiple jobs running at the same time and we would like use slurm to schedule these jobs. However, testing on a small (4 CPU) amazon server, I am unable to get this working. I would have to use `SelectType=select/cons_res` and `SelectTypeParameters=CR_CPU_Memory` as far as I know. However, when starting multiple jobs using a single CPU these are started sequentially and not in parallel.

My `slurm.conf`

===
ControlMachine=ip-172-31-37-52

MpiDefault=none
ProctrackType=proctrack/pgid
ReturnToService=1
SlurmctldPidFile=/var/run/slurm-llnl/slurmctld.pid
SlurmdPidFile=/var/run/slurm-llnl/slurmd.pid
SlurmdSpoolDir=/var/lib/slurm-llnl/slurmd
SlurmUser=slurm
StateSaveLocation=/var/lib/slurm-llnl/slurmctld
SwitchType=switch/none
TaskPlugin=task/none

# SCHEDULING
FastSchedule=1
SchedulerType=sched/backfill
SelectType=select/cons_res
SelectTypeParameters=CR_CPU_Memory

# LOGGING AND ACCOUNTING
AccountingStorageType=accounting_storage/none
ClusterName=cluster
JobAcctGatherType=jobacct_gather/none
SlurmctldLogFile=/var/log/slurm-llnl/slurmctld.log
SlurmdLogFile=/var/log/slurm-llnl/slurmd.log

# COMPUTE NODES
NodeName=ip-172-31-37-52 CPUs=4 RealMemory=7860 CoresPerSocket=2 ThreadsPerCore=2 State=UNKNOWN PartitionName=test Nodes=ip-172-31-37-52 Default=YES MaxTime=INFINITE State=UP
====

`job.sh`
===
#!/bin/bash
sleep 30
env
===

Output when running jobs:
===
ubuntu@ip-172-31-37-52:~$ sbatch -n1 -N1 job.sh
Submitted batch job 2
ubuntu@ip-172-31-37-52:~$ sbatch -n1 -N1 job.sh
Submitted batch job 3
ubuntu@ip-172-31-37-52:~$ sbatch -n1 -N1 job.sh
Submitted batch job 4
ubuntu@ip-172-31-37-52:~$ sbatch -n1 -N1 job.sh
Submitted batch job 5
ubuntu@ip-172-31-37-52:~$ sbatch -n1 -N1 job.sh
Submitted batch job 6
ubuntu@ip-172-31-37-52:~$ sbatch -n1 -N1 job.sh
Submitted batch job 7
ubuntu@ip-172-31-37-52:~$ squeue
JOBID PARTITION NAME USER ST TIME NODES NODELIST(REASON) 3 test job.sh ubuntu PD 0:00 1 (Resources) 4 test job.sh ubuntu PD 0:00 1 (Priority) 5 test job.sh ubuntu PD 0:00 1 (Priority) 6 test job.sh ubuntu PD 0:00 1 (Priority) 7 test job.sh ubuntu PD 0:00 1 (Priority) 2 test job.sh ubuntu R 0:03 1 ip-172-31-37-52
===

The jobs are run sequentially, while in principle it should be possible to run 4 jobs in parallel. I am probably missing something simple. How do I get this to work?

Best,
Jan

Reply via email to